blk_add_trace_rq_issue 1120 kernel/trace/blktrace.c 	ret = register_trace_block_rq_issue(blk_add_trace_rq_issue, NULL);
blk_add_trace_rq_issue 1168 kernel/trace/blktrace.c 	unregister_trace_block_rq_issue(blk_add_trace_rq_issue, NULL);